JP2003319237A - Digital camera and automatic focus adjusting-method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a digital camera capable of quickly making a focus even in photographing a moving picture. <P>SOLUTION: This digital camera 10 includes a brightness measuring and distance measuring circuit 25, a system control circuit 31 and an operating part 32, and a photographing mode and a macro mode are set in the system control circuit 31 in accordance with the operating state of the operating part 32. The brightness measuring and distance measuring circuit 25 calculates a focusing range in image picking up in accordance with the photographing mode and the macro mode set in the system control circuit 31. When the photographing mode is a still picture photographing mode, the brightness measuring and distance measuring circuit 25 corresponds to the macro mode, and when the photographing mode is a moving picture photographing mode, the brightness measuring and distance measuring circuit 25 neglects the macro mode. An appropriate focal position is obtained in photographing a still picture and a moving picture by adjusting the focal position in the focusing range calculated in this way. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital camera capable of shooting moving images and still images, and an automatic focus adjusting method for the same.

[0002]

2. Description of the Related Art Conventionally, some digital cameras have a macro mode for photographing a short distance such that a distance to an object is within 1 m. Macro mode, for example, by setting the focus search range in the search method to a short distance,
The focus position can be adjusted for a short-distance subject in a short time. However, a digital camera capable of shooting a still image and a moving image and having a macro mode needs to turn on the macro mode in order to shoot a moving image at a short distance. Further, when shooting a moving image, the distance to the subject is not always constant. Therefore, if the macro mode is turned on, it is difficult to continuously adjust the focal position in an advantageous manner.

The digital camera described in Japanese Unexamined Patent Publication No. 10-164606 is capable of shooting moving images and still images, and is also advantageous for a close-up subject. At this time, it is detected whether or not the subject is at a short distance at the time of shooting, and if it is determined that the subject is at a short distance, the setting which was the moving image shooting mode is switched to the still image shooting mode.

[0004]

In the digital camera described in the above publication, the shooting mode is switched to the still image shooting mode when shooting a moving picture in which the subject is at a short distance. You can't shoot.

The present invention solves the above-mentioned drawbacks of the prior art, and when shooting a short-distance subject in the moving image shooting mode, the shooting mode does not change and the shooting is performed without worrying about the macro mode setting. It is an object of the present invention to provide a digital camera and an automatic focus position adjusting method therefor.

[0006]

According to the present invention, there is provided a first selection step of selecting one of a first shooting mode capable of shooting a still image and a second shooting mode capable of shooting a moving image, A second selection step of selecting one of a first focus range that is advantageous in shooting at a normal distance and a second focus range that focuses an object at a distance closer than the first focus range; Including the digital camera automatic focus position adjustment method,
In the first shooting mode, the focusing operation is performed within the focus range selected in the second selection step, and in the second shooting mode, regardless of the selection state in the second selection step, A focusing step of performing a focusing operation in a range including the in-focus range of 1.

Further, the digital camera including the focusing control means for adjusting the focus position of the subject sets either the first photographing mode capable of photographing a still image or the second photographing mode capable of photographing a moving image. Either the first setting unit or the first focusing range that is advantageous in shooting at a normal distance and the second focusing range that focuses on a subject closer than the first focusing range are set. It includes a second setting means and a main control means for controlling the focus control means in response to the first and second setting means, and the main control means controls the second setting means in the first photographing mode. In the second photographing mode, the focusing control means is caused to perform the focusing operation within the focusing range set by the setting means, and the first focusing range is set regardless of the setting by the second setting means. It is characterized in that the focusing control means is caused to perform a focusing operation in a focusing range including

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of a digital camera according to the present invention will be described in detail with reference to the accompanying drawings.

As shown in FIG. 1, the digital camera 10 of the embodiment has an optical lens system 21, a solid-state image pickup device 22, a signal processing unit 23, a buffer memory 24, a photometry / distance measurement control circuit 25, a timing generation circuit 26, It has a recording device 27, an image display unit 28, a system control circuit 31, and an operation unit 32.

The digital camera 10 of this embodiment has a shooting mode including a still image shooting mode and a moving image shooting mode,
Further, it has a macro mode that can be set on and off, and these are controlled by the system control circuit 31. In the present embodiment, for example, as shown in FIG. 2, when the shooting mode is the still image shooting mode, the focus search range varies depending on the macro mode setting. At this time, if the macro mode is set to ON, a predetermined range close to the subject, for example, 1 m
From 0.2 m to the in-focus search range, and if it is set to off, the in-focus range is set to 1 m from infinity in other cases. When the shooting mode is the moving image shooting mode, the focus search range is set to a range including both of the above-described focus search ranges, for example, 0.2 m from infinity, without being affected by the macro mode setting state.

The optical lens system 21 has a zoom mechanism / focal length adjusting (AF) mechanism and a light amount adjusting (AE) diaphragm mechanism (both not shown). These mechanisms are
It is driven by the control signal 204 supplied from the distance measurement control circuit 25. In the following description, signals are designated by the reference signs of the connecting lines in which they appear.

The photometry / distance measurement control circuit 25 is controlled by a control signal 211 supplied from the system control circuit 31. Control signal 211 includes signals representing a shooting mode and a macro mode. The photometry / distance measurement control circuit 25 finds the in-focus range from the shooting mode and macro mode and determines the optical lens system 21.
It has a focus control function for controlling the drive of the.

As the solid-state image pickup device 22, a CCD image pickup device or the like is used in this embodiment. A subject image is formed on the solid-state image sensor 22 by the optical lens system 21, the subject image is photoelectrically converted according to a timing pulse 205 input from the timing generation circuit 26, and an electric signal 202 as an image signal is converted into a signal processing unit 23. Supply to. The timing pulse 205 is generated from a reference operating frequency (not shown) supplied from the system control circuit 31.

The signal processing unit 23 has a function of signal processing of an image signal, and adjusts white balance, gamma processing, and analog / digital (A / D) with respect to the electric signal 202 of the image signal input from the solid-state image pickup device 22. / D) conversion and luminance / dye signal conversion (YC) and the like, and stores it in the buffer memory 24 for temporary storage. It also performs compression / expansion processing for writing and reading to the recording device 27. Further, the YC signal subjected to image processing for image display in the image display unit 28 is thinned out and digital / analog (D / A) conversion is also performed. The image display unit 28 is a signal processing unit.
The image data supplied from 23 is displayed on the liquid crystal display device 406 (FIG. 4) as a visible image.

The recording device 27 is an information recording medium (not shown).
In addition, it has a function of reading image data from the buffer memory 24 and writing to the information recording medium, and a function of reading image data from the information recording medium and writing to the buffer memory 24. As the information recording medium, a memory card having a semiconductor memory mounted therein, a package accommodating a rotary recording medium such as a magneto-optical disk, or the like may be used, and the information recording medium may be removable.

In the moving image mode, the image signal is compressed in the motion JPEG system and recorded in the recording device 27. That is, after the electric signal of the image signal is once stored in the buffer memory 24, the still image is continuously stored in the information recording medium in the recording device 27 while performing the signal processing and performing JPEG compression within one image.

The operation unit 32 includes a power switch 401 and a shutter release button as shown in FIGS. 3 and 4, for example.
The input / selection switches 402, the photographing mode switch 403, the macro button 404, the cross key 405, and the like are supplied to the system control circuit 31 by an operation signal 215. The shooting mode switch 403 is, for example, a slide switch, and selectively sets a still image shooting mode and a moving image shooting mode.

The system control circuit 31 has a main control function of controlling and controlling the operation of the entire apparatus in response to an operation signal 215 supplied from the operation section 32. In this embodiment, the system control circuit 31 determines the shooting mode and the macro mode from the operation states of the shooting mode switch 403 and the macro button 404 indicated by the operation signal 215. Particularly in relation to the present invention, the system control circuit 31 supplies the determined photographing mode and macro mode to the photometry / distance measurement control circuit 25 by the control signal 211.

Next, the operation of the digital camera 10 will be described. The operator operates the operation unit 32 of the camera 10, first operates the shooting mode switch 403 to set the still image shooting mode or the moving image shooting mode, and operates the macro button 404 to turn it on or off. Next, shutter release
When 402 is pressed, the system control circuit 31 responds to the operation signal 215 from the operation unit 32 to cause the timing generation circuit 26, the photometry / distance measurement control circuit 25 and the signal processing unit 23 to control signals 212, 211 and 213, respectively. , Or a reference operating frequency (not shown). In the timing generation circuit 26, the timing pulse 205 having a frequency asynchronous with the reference operating frequency is used.
And 206 are generated and supplied to the solid-state imaging device 22 and the signal processing unit 23, respectively. In addition, the shooting mode switch 403
The operation state of the macro button 404 and the macro button 404 is transmitted from the operation signal 215 to the system control circuit 31, and the system control circuit 31 controls the setting state of the photographing mode and macro mode 2
Notify the photometry / distance measurement control circuit 25 by 11.

The photometry / distance measurement control circuit 25 determines the photographing mode (step 301) as shown in FIG. If the shooting mode is the still image shooting mode, the macro mode is determined (step 302). Photometry / distance measurement control circuit 25
Displays the focus search range 1 m when the macro mode is on.
To 0.2 m (step 303), and when it is off, the focus search range is set from infinity to 1 m (step 304) and the process proceeds to still image shooting (step 305). Also,
When the shooting mode is the moving image shooting mode, the macro mode determination (step 302) is not performed and the process proceeds to step 310 and the focus search range is 0.2 m from infinity (step 31).
Set it to 0) and proceed to movie shooting (step 311). The photometry / distance measurement control circuit 25 controls the optical lens system 21 to adjust the focus position according to the obtained focus search range and the result of the distance measurement obtained from the optical lens system 21. The subject image is formed on the solid-state image pickup device 22 by the optical lens system 21, and the solid-state image pickup device 22 controlled by the timing generation circuit 26 photoelectrically converts the subject image to generate an electric signal 202 which is an image signal.

The image signal 202 is supplied to the signal processing unit 23 where it is subjected to signal processing and the image signal 203 which is the result of the signal processing is supplied.
Are temporarily stored in the buffer memory 24. The system control circuit 31 controls the recording device 27 by the control signal 217, and the recording device 27 controls the reading and writing of the image signal between the image signal in the buffer memory 24 and the information recording medium. Further, the system control circuit 31 controls the image display unit 28 by the control signal 218, supplies the image signal in the buffer memory 24 to the image display unit 28, and displays it on the liquid crystal display device 406 as a visible image.

In the present embodiment, in the moving image photographing mode, regardless of the setting state of the macro mode, even if the subject is at a short distance, it does not fall out of the focus search range, and it is the same as photographing at a normal distance. The focus position is advantageously adjusted. This allows the operator to continuously shoot a moving image without worrying about the setting state of the macro mode.

In this embodiment, the photometry / distance measurement control circuit 25
In, the focusing range is obtained from the shooting mode and macro mode. However, such a configuration is not always necessary. For example, the system control circuit 31 obtains the focusing range by the flow shown in FIG. 2, and the focusing range is controlled by the control signal 211.
By supplying the signal to the photometry / distance measurement control circuit 25 by means of the above, the signal transmitted by the control signal 211 can be reduced.

As another embodiment, the digital camera 10 has two or more focusing methods, and the control signal 211
The photometry / distance measurement control circuit 25 may be configured to select the focus method in accordance with the shooting mode supplied by. For example, when the shooting mode is the still image shooting mode, the search method is used, and when the shooting mode is the moving image mode, the continuous method (hill climbing method) is used. At this time, since the image pickup in the moving image mode is not the search method, the setting state of the macro mode does not affect the adjustment of the focus position at the time of moving image shooting.

[0025]

As described above, according to the present invention, when the digital camera is in the still image shooting mode, the focusing time required for short-distance shooting is shortened by responding to the setting state of the macro mode, and the moving image shooting mode is achieved. In case of, by ignoring the macro mode setting and widening the focusing range,
An advantageous focus position can be obtained in correspondence with short-distance photography.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a digital camera to which the present invention is applied.

FIG. 2 is a flowchart showing an example of control for selecting a focusing search range in the photometry / distance measurement control circuit 25 of the embodiment shown in FIG.

FIG. 3 is a top view showing the external appearance of the digital camera of the embodiment.

FIG. 4 is a rear view showing the outer appearance of the digital camera according to the embodiment.

[Explanation of symbols]

10 Digital still camera 21 Optical lens system 22 Solid-state image sensor 23 Signal processor 24 buffer memory 25 Metering / distance measurement control circuit 26 Timing generator 27 Recording device 28 Image display area 29 System control unit 30 Control 401 power switch 402 Shutter release button 403 Shooting mode switch 404 macro button 405 Four-way controller 406 Liquid crystal display

Claims (6)

[Claims] 1. A first shooting mode capable of shooting a still image,
Unlike the first shooting mode, the first selection step of selecting one of the second shooting modes capable of shooting a moving image, the first focusing range advantageous in shooting at a normal distance, and the first shooting range Focusing on a subject closer than the focusing range of 1st 2nd
And a second selection step of selecting any one of the focusing ranges of the digital camera, the method further comprising:
Focusing operation is performed within the focusing range selected in the selection step of
In the second photographing mode, the automatic focusing of the digital camera including the focusing step of performing the focusing operation in the range including the first focusing range regardless of the selection state in the second selection step. Focus position adjustment method. 2. The method according to claim 1, wherein in the focusing step, a focusing operation is further performed in a range including a second focusing range in the second shooting mode. Automatic focusing method for digital camera. 3. The method according to claim 1, wherein in the focusing step, a focus position is adjusted by a search method in the first shooting mode, and a hill climbing method is used in the second shooting mode. An automatic focus position adjusting method for a digital camera, characterized by adjusting a focus position. 4. A digital camera including a focusing control means for adjusting a focus position of a subject, wherein the camera is capable of capturing a moving image, unlike a first capturing mode capable of capturing a still image and a first capturing mode. First setting means for setting one of the second shooting modes capable of shooting, a first focus range advantageous for shooting at a normal distance, and a subject closer than the first focus range. Second to burn
A second setting means for setting any one of the focusing ranges and a main control means for controlling the focus control means in response to the first and second setting means. In the first shooting mode, the focusing control means is caused to perform the focusing operation within the focus range set by the second setting means, and in the second shooting mode, the second setting is performed. A digital camera characterized in that the focusing control means is caused to perform a focusing operation within a focusing range including a first focusing range regardless of the setting by the means. 5. The digital camera according to claim 4, wherein the main control means, in the second photographing mode,
Further, the digital camera is characterized in that the focusing control means is caused to perform a focusing operation within a range including a second focusing range. 6. The digital camera according to claim 4, wherein the main control unit causes the focusing control unit to adjust a focus position by a search method in the first photographing mode,
A digital camera characterized in that the focus position is adjusted by a hill climbing method in the second photographing mode.